This report provides a brief summary of earthquake activity recorded by the U.S. Geological Survey Northern California Seismic Network in Menlo Park and the University of California Berkeley Seismological Laboratory. It is automatically generated each Wednesday shortly after midnight, Universal time (UT). UT (ie., Greenwich Mean Time) is 8 hours ahead of PST or 7 hours ahead of PDT.
Because it is not possible to review all of the earthquakes before this report is generated, it may contain errors. Please report errors or provide suggestions and comments to ncsn@usgs.gov
The report no longer includes maps showing earthquakes for the entire US or world. Those maps are now available from the U.S.G.S. National Earthquake Information Center. In addition, all earthquake data can be retrieved from the Northern California Earthquake Data Center.
Please note that some of the earthquake data in this report have been reviewed by seismic analysts. Consequently, the parameters that describe the hypocenter, magnitude, origin time, and solution statistics may differ slightly from the information contained on the real-time earthquake web page. The differences reflect revised arrival times at seismic stations and the analysts' decisions to include or exclude information from seismic stations.
The minimum magnitude ( M) values in the following bullets reflect the smallest earthquake which the network can routinely record within the region. During the previous seven-day period ending at midnight (UT) Wednesday, our seismic networks recorded
The largest event to occur this week in this region was a minor earthquake of magnitude 3.8 2 miles E of Ben Lomond, CA at 12:38 PM UTC Tuesday, Dec 29, 1998 (04:38 AM PST Tuesday, Dec 29, 1998).
The largest event to occur this week in this region was a minor earthquake of magnitude 3.8 2 miles E of Ben Lomond, CA at 12:38 PM UTC Tuesday, Dec 29, 1998 (04:38 AM PST Tuesday, Dec 29, 1998).
That magnitude 3.8 earthquake was preceded by a magnitude 3.0 quake at 2:01 am in the same location and followed by over two dozen aftershocks, the largest of which was magnitude 3.5 at 4:41 am. This sequence of quakes appeared to be on the Zyante fault and this specific location has not had many earthquakes since the late 1960's. The largest earthquake in the region in recent years was the October 1989 Loma Prieta magnitude 7.0 earthquake that occurred about 10 miles to the southeast. The following list shows magnitude 3.0 or larger quakes that have occurred within approximately 5 miles of this magnitude 3.8 quake since the late 1960's.Date Time (UT) Lat Lon Depth Mag ------------------------------------------------------- 1970/07/11 19:01:03.76 37.1422 -121.9975 13.52 3.40 1987/09/26 05:53:53.32 37.1407 -121.9867 16.07 3.00 1989/10/18 00:16:54.19 37.0920 -121.9523 0.01 4.10 1989/10/18 00:17:13.50 37.1325 -122.0045 12.87 3.40 1989/10/18 00:17:56.87 37.1432 -122.0500 21.63 3.20 1989/10/18 00:30:41.23 37.1197 -121.9870 15.94 4.20 1989/10/18 00:33:36.54 37.1397 -122.0027 7.01 3.20 1989/10/18 00:58:56.25 37.1192 -121.9762 14.79 3.90 1989/10/18 01:03:59.45 37.0767 -121.9910 4.99 3.70 1989/10/18 01:05:33.79 37.1365 -121.9922 13.36 3.10 1989/10/18 01:25:34.79 37.1308 -121.9860 13.25 3.10 1989/10/18 02:17:25.40 37.1298 -121.9675 10.43 3.20 1989/10/18 03:23:56.19 37.1358 -121.9895 15.03 4.00 1989/10/18 03:30:11.36 37.1367 -121.9893 15.21 4.20 1989/10/18 04:14:47.97 37.1317 -121.9835 15.14 3.50 1989/10/18 05:38:01.95 37.1362 -122.0455 18.16 3.20 1989/10/19 01:51:25.18 37.1423 -121.9868 14.14 3.00 1989/10/19 21:15:34.09 37.1232 -121.9852 15.94 3.20 1989/10/20 14:15:30.75 37.1023 -121.9690 5.75 3.40 1989/12/12 03:52:00.99 37.1438 -121.9808 13.08 3.60 1990/10/05 06:04:17.69 37.0742 -122.0153 12.77 3.60 1991/06/03 00:40:45.43 37.1392 -121.9930 14.80 3.10 1998/12/29 10:01:21.80 37.0955 -122.0367 10.13 3.00 1998/12/29 12:38:12.37 37.0918 -122.0423 10.11 3.80 1998/12/29 12:41:39.21 37.0970 -122.0332 10.00 3.48
The largest event to occur this week in this region was a microearthquake of magnitude 2.2 5 miles SE of Mammoth Lakes, CA at 07:34 AM UTC Monday, Dec 28, 1998 (11:34 PM PST Sunday, Dec 27, 1998).
The following table provides a listing of all M >2 earthquakes that occurred this week. An explanation of the entries in the table is available.
--ORIGIN TIME (UT)-- -LAT N-- --LON W-- DEPTH N N RMS ERH ERZ LOC PREF YR MON DA HRMN SEC DEG MIN DEG MIN KM RD S SEC KM KM REMKS MAG 98 DEC 24 634 34.74 40 18.73 124 33.92 20.14 49 1 .09 .6 .3 MEN 3.3D 98 DEC 24 803 30.02 38 44.61 122 55.86 3.76 25 .07 .2 .9 ROG 2.1D 98 DEC 24 1758 0.52 40 38.35 122 24.39 23.83 12 .03 .4 .4 SHA 2.1D 98 DEC 25 100 48.70 38 51.45 122 49.36 2.04 19 .05 .2 .6 GEY 2.4D 98 DEC 25 101 21.23 38 51.38 122 49.67 1.77 9 .03 .4 .7 GEY 2.0D 98 DEC 25 343 57.14 41 15.93 123 23.79 39.13 49 1 .19 .3 .4 KLA 3.5D 98 DEC 25 519 51.60 38 47.47 122 46.20 5.26 47 .07 .1 .3 GEY 3.7D 98 DEC 25 1012 41.22 35 49.42 121 17.07 8.72 57 2 .05 .2 .4 SSM 2.4D 98 DEC 25 1037 34.32 35 49.46 121 16.96 8.52 45 2 .05 .2 .5 SSM 2.1D 98 DEC 26 257 52.07 37 32.62 118 42.21 7.89 29 .05 .2 .6 WCN 2.2D 98 DEC 26 606 55.91 40 45.13 124 25.99 21.75 31 1 .05 .4 .6 EUR 2.5D 98 DEC 26 1002 37.40 36 17.05 120 18.03 5.28 8 .02 .3 .7 COA 2.2D 98 DEC 26 1030 45.22 40 37.71 122 25.00 23.89 11 .06 .4 .7 SHA 2.4D 98 DEC 26 1831 22.89 38 49.09 122 48.14 5.49 41 .07 .2 .3 GEY 2.9D 98 DEC 27 317 14.54 37 36.39 118 51.79 4.47 24 .08 .3 .4 SHE 2.2D 98 DEC 27 2129 42.44 38 48.70 122 47.94 2.41 23 .04 .2 .3 GEY 2.2D 98 DEC 28 734 5.73 37 36.06 118 54.87 7.63 29 .07 .3 .4 SHE 2.2D 98 DEC 28 1220 14.61 39 3.06 123 3.32 8.20 22 .05 .2 .6 MAA 2.0D 98 DEC 28 2029 30.24 38 30.78 122 15.18 3.14 44 .23 .3 1.1 GVL 2.9D 98 DEC 29 755 41.14 37 28.44 118 50.73 6.80 29 .06 .3 .9 MOR 2.2D 98 DEC 29 1001 21.80 37 5.73 122 2.20 10.13 80 3 .09 .2 .3 MON 3.0D 98 DEC 29 1238 12.37 37 5.51 122 2.54 10.11 95 5 .12 .2 .4 MON # 3.8D 98 DEC 29 1239 56.17 37 5.01 122 3.84 8.31 13 .06 .3 .9 MON 2.6D 98 DEC 29 1241 23.01 37 5.63 122 2.49 8.12 29 .07 .2 .4 MON 1.8D 98 DEC 29 1241 39.21 37 5.82 122 1.99 10.00 85 3 .10 .2 .3 LOM 3.5D 98 DEC 29 1417 15.78 37 5.76 122 2.63 9.47 52 .09 .2 .4 MON 2.3D 98 DEC 29 2339 59.85 38 49.07 122 50.16 1.53 18 .05 .2 .5 GEY 2.1D 98 DEC 30 309 50.47 38 48.80 122 48.86 3.73 28 .08 .2 .5 GEY 2.3D 98 DEC 30 501 33.36 38 47.66 122 46.61 0.94 16 .04 .2 .5 GEY 2.4D
